I recently implemented stripe checkout in my site which runs on Pythonanywhere. Initially, I followed the recipe in the manual, using /gluon/contrib/stripe.py. Worked in local test, but failed on my test site which is a free Pythonanywhere account, although PA say Stripe is whitelisted.
This version does work on free Pythonanywhere accounts.
According to Pythonanywhere support, the /gluon/contrib/stripe.py implementation does something that the proxy used for free PA accounts doesn't like.
Suggest the manual recipe refer to the stripe API docs.